STEADY & UNSTEADY STATE HEAT TRANSFER

 HEAT TRANSFER

WHAT IS HEAT TRANSFER ?

• Heat transfer is a form of energy transmit due to temperature difference . Heat transfer is a transmission of energy from one region to another region as a result of temperature difference
• Heat is a path function . heat flow from high temperature to lower temperature

transfer heat high body to lower body

STEADY STATE HEAT TRANSFER

• There is no change in heat transfer with time at any point in a direction within the medium
• dQ/dT = 0 ,  here Q is heat transfer
• In this case of energy transfer the temperature is only function of space-coordinate , not a function of time, mathematically for rectangular coordinate system 
•  T=f(x,y,z)

for example of steady state heat transfer

• Heat exchanger with fluid flow
• Heat generation due to electric current

UNSTEADY STATE HEAT TRANSFER

• Change in heat transfer at any point with time in direction within the medium is called as unsteady heat transfer
• Q is heat transfer is not equal to zero
• In this case of energy transfer the temperature is function of space co-ordinate as well as time, mathematically for rectangular co-ordinate system (depends on time)
• T = f(x,y,z,T)

MODES OF HEAT TRANSFER

• CONDUCTION HEAT TRANSFER

• CONVECTION HEAT TRANSFER

• RADIATION HEAT TRANSFER

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